Why don't the disks on Nev's ult stack damage?

(tiny rant)

"Damage from multiple Catarangs does not stack." Why? Every other multihit ability in the game stacks damage on multiple hits, but Nev's ult doesn't for some reason. And considering that it's an ultimate ability, it really should give a reason to use it other than "moar area." It just looks like an arbitrary stat, and it's really inconsistent with other abilities in the game. Is there an official reason for this?

Official reason:
because Devs wanted to create firepower without attacks that deal burst damage, BUT with lot of ways to deal consistent damage often and easy utilizing huge AoE of her attacks and constantly returning catarings now and then so she would not have problems with low damage output per turn. (she's very good anti-group firepower like Elle or Juno with anti-melee function because her attacks don't stop on single target, but go through everyone that is in AoE of her attack.)
Unofficial reason:
she's pretty overpowered in current form after buff, so after this upgrade she would become perma-banned on rankeds like good old Quark that been nerfed to the ground so it is viable only when You have pre-made team with VoIP and very good positioning skills.